14-3-3:Shc scaffolds integrate phosphoserine and phosphotyrosine signaling to regulate phosphatidylinositol 3-kinase activation and cell survival

J Biol Chem. 2009 May 1;284(18):12080-90. doi: 10.1074/jbc.M807637200. Epub 2009 Feb 13.

Abstract

Integrated cascades of protein tyrosine and serine/threonine phosphorylation play essential roles in transducing signals in response to growth factors and cytokines. How adaptor or scaffold proteins assemble signaling complexes through both phosphotyrosine and phosphoserine/threonine residues to regulate specific signaling pathways and biological responses is unclear. We show in multiple cell types that endogenous 14-3-3zeta is phosphorylated on Tyr(179) in response to granulocyte macrophage colony-stimulating factor. Importantly, 14-3-3zeta can function as an intermolecular bridge that couples to phosphoserine residues and also directly binds the SH2 domain of Shc via Tyr(179). The assembly of these 14-3-3:Shc scaffolds is specifically required for the recruitment of a phosphatidylinositol 3-kinase signaling complex and the regulation of CTL-EN cell survival in response to cytokine. The biological significance of these findings was further demonstrated using primary bone marrow-derived mast cells from 14-3-3zeta(-/-) mice. We show that cytokine was able to promote Akt phosphorylation and viability of primary mast cells derived from 14-3-3zeta(-/-) mice when reconstituted with wild type 14-3-3zeta, but the Akt phosphorylation and survival response was reduced in cells reconstituted with the Y179F mutant. Together, these results show that 14-3-3:Shc scaffolds can act as multivalent signaling nodes for the integration of both phosphoserine/threonine and phosphotyrosine pathways to regulate specific cellular responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / genetics
  • 14-3-3 Proteins / metabolism*
  • Animals
  • Cell Line
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Enzyme Activation / physiology
  • Granulocyte-Macrophage Colony-Stimulating Factor / pharmacology
  • Humans
  • Mast Cells / cytology
  • Mast Cells / metabolism
  • Mice
  • Mice, Knockout
  • Mutation, Missense
  • Phosphatidylinositol 3-Kinases / genetics
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation / drug effects
  • Phosphorylation / physiology
  • Phosphoserine / metabolism*
  • Phosphotyrosine / metabolism*
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Shc Signaling Adaptor Proteins / genetics
  • Shc Signaling Adaptor Proteins / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*

Substances

  • 14-3-3 Proteins
  • Shc Signaling Adaptor Proteins
  • Phosphoserine
  • Phosphotyrosine
  • Granulocyte-Macrophage Colony-Stimulating Factor
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt